International cargo containers are standardized in various lengths such as 20, 24, 40, 45, 48 and 53 ft. The standardized cargo containers are regularly stacked one on top of another on a railway freight car for transport.
The ever increasing demand to increase the payload of railway cars and commercial competitiveness has forced manufacturers to design lighter railway cars which can still safely withstand the various dynamic forces which act upon the cargo containers during transport.
U.S. Pat. No. 4,599,949, discloses a light weight container car. The container car comprises a pair of longitudinally extending side sills of double web construction welded to a plurality of transverse beams and cross beams for strengthening the side sills from lateral deflection. Two cross beams are welded to a centered pad and extend between adjacent transverse beams.
U.S. Pat. No. 4,771,706, discloses a container carrying railroad car with supporting castings. The car body has opposing side walls and end walls defining a well in which a container can be received. The supports for the bottom of the container within the well has a plurality of metal castings joined to each side wall. Each casting has a substantially vertical leg joined to an exterior stiffener on the side wall and an arm extending substantially horizontally inward under the side chord or angle towards the center of the car on which a container bottom can be supported.
U.S. Pat. No. 4,909,157, discloses a railway car having a plurality of spaced metal castings joined to each side wall. Each casting has an L-shape with the vertical leg joined at the bottom the side wall to an exterior stiffener and the arm of the casting extending laterally horizontally inwardly under the side bottom chord or angle to aid in supporting a container in the well.
In order to stack two cargo containers, the railroad car must have a well to carry the two stacked containers as low as possible to meet the height restrictions of the rail system. The load bearing surfaces are generally vertically offset from the support points and the coupling points of the railroad car. As a result, unbalanced moments are created which must be counterbalanced with an opposite moment.
U.S. Pat. No. 4,599,949 discloses an end bulkhead joined to the side sills. The bulkhead has a plurality of strengthening baffles.
U.S. Pat. No. 4,807,722, discloses a railway car wherein each end of the car has a stub sill knee to transfer loads from the coupling to a lower horizontal shear plate in the well areas which can collect snow which must be cleared before loading the car.
Although these patents effectively counterbalance the unbalanced moments, the structure has not been fully satisfactory.
Intermodal cargo containers are also standardized in terms of width. A cargo container can have either a 96 inch or 102 inch width. A well of a railroad freight car is generally manufactured to receive the larger width container. However, if a narrower width container is loaded into the wider well, the narrower container is prone to overturn within the container well. Retractable guides have been proposed to effectively narrow the width of the container well.
U.S. Pat. No. 4,754,709, discloses a railway car for carrying a container. The car body has opposing side walls having guides mounted along each side for reducing the width of the wells spaced therebetween so as to center in the well, a container having a width less than the well width so as to limit sideward movement of the container in the well when the car rocks. However, such guides must be deployed prior to the container being deposited in the well, since the guide pivots through a space which is occupied by the container after it has been deposited in the well.
U.S. Pat. No. 4,930,426, discloses a device for changing the effective width of a container well of a freight car. A guide body is slid laterally inwardly and locked in the inner position for guiding a narrower container. A latch comprising a bar and aperture is used to lock the guide body in either the inner or outer position. However, the latch is prone to jam with ice under freezing conditions and therefore will lock in a particular position.